Add Chex cereal, mini pretzels, and cinnamon cereal to a large mixing bowl. Gently toss until evenly combined, making sure not to crush the cereal pieces.

Melt the butter in a microwave-safe bowl in short intervals, stirring between each one. Once fully melted, stir in vanilla and salt until smooth and well mixed.

Slowly pour the melted butter mixture over the cereal mix, moving around the bowl as you pour. Gently fold the mixture with a spatula until all pieces are lightly coated.

In a separate bowl, mix sugar and cinnamon together until fully blended and evenly colored.

Sprinkle the cinnamon sugar mixture over the coated cereal in small batches. Toss gently after each addition to ensure even coating across all pieces.

Transfer the coated mix onto a parchment-lined baking sheet. Spread it out into an even layer without pressing it down.

Allow the mix to cool at room temperature for 10 to 15 minutes until the coating sets and becomes slightly crisp. Break apart any large clusters before serving.